How do I measure H2 in solution ?

I have the problem that I want to measure hydrogen in solution, to make it
even more difficult I want to measure it in very small samples (e.g. about
100 microliters). This doesn't have to be quantitatively but I just need
to know if it is more or less compared to the next sample.
Anybody got an idea how to accomplish that easy and cheap ?
Hayssam